Re: [OM] Awww, poop.

[Andrew Fildes]

No. The rear doublet is very small and odd but doesn't suffer this way. The 
problem occurs in the space between that and the next element - the two 
opposing surfaces haze over and become etched - they can be repolished and 
single recoated by specialist services. As to what causes it in just one 
specific location - that's a mystery. There's no lubricant in there (the lens 
focuses by a simple helical that moves the whole lens unit forward) and the 
elements are held in place by simple spacer rings in a tube. My bet is a 
failure of specialised coatings on just those two surfaces.
Andrew Fildes
afildes@xxxxxxxxxxxxx
www.soultheft.com
Author/Publisher: The SLR Compendium - http://www.blurb.com/books/3732813



On 07/02/2013, at 2:49 AM, Sawyer, Edward wrote:

> The OM 8mm fisheye lens suffers from this same endemic failure. Almost all
> of them have a clouded element in the rear. It must be some sort of issue
> with the cement in a cemented pair of elements.

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